Intra-aortic balloon pumping (IABP) has become a standard treatment modality for cardiogenic shock in adults but has been used only sparingly in infants. This is due in part to the limitations of the currently available drive systems which are designed to meet the physiologic needs of an adult. A balloon pump, which is specifically tailored to the small volumes and higher rates often seen in pediatric cases will be fabricated and tested on a mock circulation system. Comparisons to commercially available drive systems will be made in vitro and then the data validated by a series of in vivo experiments using dogs. Appropriate IABP equipment would then be available for use in infants and children whenever low cardiac output syndrome in present. Additional clinical experience might then lead to expanded use in cases of myocarditis or sepsis.